Furnace.



PATENTED JUNE l2, 1906. J. A. KAVANAGH.-

FURNAGB.

APPLICATION PILBD'AUG. 9, 1905.

tial combustion to the boiler.

UNITED STATES PATENT OFFICE.

FURNACE.

Specification of Letters Patent,

Patented June 12, 1906.

Application led August 9, 1905. Serial No. 273,397.

To LZZ whom t may concern.-

Be it known that I, JAMES A. KAVANAGH, of New York, in the county ofKings and State of New York, have invented certain new and usefulImprovements in Furnaces; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

This invention relates to that class of steam-boiler furnaces in whichthe products from the initial combustion pass through a bed ofincandescent fuel for the purpose of thoroughly igniting theircombustible constituents to obviate the creation of smoke and increasethe efficiency of the consumed gases for the creation of steam.

The primary object of the invention is to provide improved means forintroducing fresh heated air at such points relative to the secondarycombustion on the bed of incandescent fuel as to insure the thoroughcon-l sumption and heating of the products and gases.

In the accompanying drawings, Figure 1 is a vertical longitudinalsectional view of a furnace equipped with my improvement, the furnacebeing applied to an ordinary land or stationary tubular boiler. Fig. 2is a transverse sectional view showing the bridge-wall in frontelevation.

Referring to the drawings, 1 designates the steam-boiler suitablymounted in a setting of masonry.

2 is the bridge-wall extending from the bottom of the furnace to andpartly surrounding the boiler-shell to form a baffle and prevent thedirect passage of the gases from the ini- Near its base the bridge-wallis provided with a plurality of transverse orifices 3, extendingentirely through the same. Forward of the bridgewall the furnac'e isdivided by a partition 4 to provide an ash-pit 5 and combustion-chamber6, the latter also serving as a subsidencereceptacle for incombustibleashes.

7 is a grate over the ash-pit supported by the partition 4 and the frontwall of the furnace. 8 is a second grate over the combustion-chamberspanning the space between the partition 4 and the bridge-wall. Thisgrate 8 is a water-tube grate, shown connected at one end with thewater-space and at the other end with the steam-space of the boiler.

The partition 4 is provided at its base with an opening affording accessfrom the front of the furnace to the combustion-chamber 6 for thepurpose of cleaning the latter. A door 9 normally closes this openingand is oon'- trolled by a handle 10, extending through the ash-pit tothe front of the furnace within reach of the attendant.

In each side wall of the furnace I provide an air-inlet passage 12,having its outer extremity open to the atmosphere, preferably at therear end of the furnace and extending inwardly to a point over` thepartition 4. The portion of each of these air-passages in advance of thebridge-wall and above the grate S is provided with a plurality ofoutlet-ports 13 and a channel 14, extending vertically downward to apoint within the combustionchamber and beneath the grate 8. Near theirlower extremities and below the grate the channels 14 are formed withoutlet-ports 15, opening into the combustion-chamber.

At 16 is shown an air-duct in the bridgewall extending throughout thewidth thereof in alinement at either end with conduits 17, leading fromthe passages 12. The duct is formed with outlet-ports 18, opening in thefront face of the bridge-wall and has branches 19 extending downwardlyand constituting fiues with outlet-ports 20 at a point in thebridge-wall below the grate 8, so that the latter is arrangedintermediate these ports and ports 18.

In practice'the fire is made on grate 7 in the usual manner, and afterattaining a certain degree of combustion a portion of the fuel is pushedback upon the water-grate S. Air passes by the natural draft up throughthe grate 7 from the ash-pit, after which the ases and consumed productsare drawn ownwardly through the water-grate and bed of incandescent fuelthereon. Between their leaving the first grate and entering the second,however, highly-heated fresh air entrained from passages 12 in thefurnacewalls and from duct 16 in the bridge-wall is mixed with the gasesand effects a more thorough combustion than may have resulted upon thefirst grate. After passing through the second grate and into thecombustion-chamber the gases are caught in a third draft of heated freshair issuing from the channels 14 and likewise encounter the air fromflues 19. Ample opportunity is here aorded for thoroughly mixing thegases IOO with the supply of heated air, effecting complete combustionof the carbon and unconsumed gases, after which the line of direction isthrough the orifices 3 of the bridge-wall and thence by way of theuptake to the boiler-tubes and smoke-stack.

Practice has demonstrated that the gases passing to the boiler-tubesfrom a furnace constructed in accordance with my invention areessentiaily volatile and free from solid matter carried in suspension.The air introduced at the point of initial combustion, as well as thatsubsequently mixed with the gases, is fresh and not vitiated by priorpassage over or in contact with a bed of fuel and is, furthermore,highly heated in its travel through the passages in the furnace-wallsand the duct and flues in the bridge-wall, thus reducing the possibilityof condensation to a minimum.

I claim as my inventionl. In a furnace having an initial fire-bed and agrate designed to support a bed of incandescent fuel, the draft beingupward through said fire-bed and downward through said grate, passageswithin the side walls of said furnace extending longitudinally thereofand having outlets for the introduction of air to the gases at points inthe travel of the latter intermediate the fire-bed and said grate, andchannels supplying additional air to the gases after the passage thereofthrough said grate.

2. In a furnace having an initial fire-bed and a grate designed tosupport a bed of incandescent fuel, the draft being upward through saidfire-bed and downward through said grate, air-passages in the side wallsof said furnace having outlets designed to introduce air to the gases atpoints in the travel of the latter intermediate the initial fire-bed andsaid grate, and channels leading from said passages and having outletsbelow said grate.

3. In a boiler-furnace having an initial fire-bed and a grate designedto support a bed of incandescent fuel, a bridge-wall at the rear of saidgrate extending from the bottom of the furnace to the boiler-shell,air-passages in the side walls of said furnace extending longitudinallythereof and open at the rear end of said furnace, and an air-duct insaid bridge-wall, each having outlets designed to introduce air to thegases at points in the travel of the latter intermediate the initialfire-bed and said grate.

4. In a boiler-furnace having an initial fire-bed and a grate designedto support a bed of incandescent fuel, a bridge-wall at the rear of saidgrate extending from the bottom ofthe furnace to the boiler-shell,air-passages in the side walls of said furnace and an airduct in saidbridge-wall, each having outlets designed to introduce air to the gasesat points in the travel of the latter intermediate the initial fire-bedand said grate, and channels leading from said passages and havingoutlets below said grate.

5. In a boiler-furnace having an initial fire-bed and a grate designedto support a bed of' incandescent fuel, a bridge-wa l at the rear ofsaid grate extending from the bottom of the furnace to theboiler-shell,A air-passages in the side walls of said furnace and anair- .duct in said bridge-wall, each having outlets designed tointroduce air to the gases at points in the travel of the latterintermediate the initial fire-bed and said grate, and ues leading fromsaid duct having outlets below said grate.

6. In a boiler-furnace having an initial fire-bed and a grate designedto support a bed of incandescent fuel, a bridge-wall at the rear of saidgrate extending from the bottom ofthe furnace to the boiler-shell,air-passages in the side walls of said furnace, an air-duct in saidbridge -wall conduits establishing communication between said passagesand said duct, said passages and duct having outlets designed tointroduce air to the gases at points in the travel of the latterintermediate said fire-bed and said grate, channels leading from saidpassages having outlets below said grate and flues in said bridge-wallleading from said duct and also having outlets below said grate.

7. In a boiler-furnace having an initial fire-bed and a grate designedto support a bed of incandescent fuel, a bridge-wall at the rear of saidgrate extending from the bottom of the furnace to the boiler-shell, saidbridgewall having transverse orifices near its base, the draft beingupward through said fire-bed, downward through said grate and throughsaid orifices in the bridge-wall7 air-passages in the side walls of saidfurnace having outlets designed to introduce air to the gases at pointsin the travel of the latter intermediate the initial fire-bed and saidgrate, and channels leading from said passages and having outlet-portsbelow said grate and intermediateuthe latter and said orifices of thebridgewa 8. In a boiler-furnace, a bridge-wall extending from the bottomthereof to the boilershell and having transverse orifices near its base,a partition in advance of said bridgewall forming an ash-pit and acombustionchamber, a grate between said partition and the front wall ofthe furnace, a second grate between said partition and said bridge-wall,an air-passage within a side wall of said furnace extendinglongitudinally thereof and having outlets opening above said secondgrate, and channels extending into said combustion-chamber and belowsaid second grate.

9. In a boiler-furnace, a bridge-wall extending from the bottom thereofto the boilershell and having Atransverse orifices near its IOO IIO

base, a partition in advance of said bridgewall forming'an ash-pit and acombustioncharnber, an opening near the base o1 said partition7 a doorfor controlling the same, a grate between said partition and the frontwail of the furnace, a second grate between said partition and saidbridge-wall, air-passages in the walls of said furnace having outletsabove said second grate, and channels extending into saidcombustion-chamber and( 1o below said second grate.

In testimony whereof I have signed this specification in the presence oftwo subscrib-

